To separate oil and water in a well hole is known, for example, from U.S. Pat. No. 4,296,810. The separator used is built up of semi-permeable membranes. The separated water, produced water, is injected into a waste zone above or below the production zone.
U.S. Pat. No. 4,659,343 makes known the separation of carbon dioxide from light hydrocarbons with the aid of a membrane arrangement. During the separation through the semipermeable membrane, a condensate emerges (hydrocarbons in liquid form) in contact with the membrane. These (liquified) liquid hydrocarbons are separated from the gases which do not pass through the membrane. This separation takes place by means of conventional membrane technology used in traditional processes within the processing industry.
Gravitation separation of hydrocarbons and water in a well hole is known, for example, from U.S. Pat. No. 4,766,957. The produced water flows into a waste zone and the oil passes upward to the surface.
U.S. Pat. No. 4,805,697 describes the reinjection of produced water, resulting from the separation of hydrocarbons and water in a centrifugal separator, of the dynamic or static type, regulated as a function of the hydrocarbon content in the produced water.
Hollow fiber separation (the hollow fibers are of a semipermeable membrane material) is discussed in U.S. Pat. No. 5,176,725.
NO B 173426 describes the use of cyclone separators in the separation of oil and water in a well hole.
The processing of a production flow in a well hole gives rise to great advantages, especially by virtue of the fact that one does not need to lift, separate or remove the produced water.